Separating release documentation between release tags

[kmadsen]

When a repository has multiple release channels. It has an issue of publishing documentation to the main release channel.

Both maps and navigation have separate release channels for android auto

• Maps extension-androidauto-v0.1.0
• Navigation androidauto-v0.1.0

But the documentation is part of the main release channel

• Maps androidauto docs bundled with 10.6.0-rc.1
• Navigation androidauto docs bundled with 2.6.0-alpha.2

This is not really a big deal for developer previews. But it will be an issue if one of these other release channels needs to become a stable release. We'll want to have documentation bundled with the specific versions

cc: @MrSwimmer @pengdev @mikelmaron